共查询到19条相似文献，搜索用时 109 毫秒
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本文报导了南方大口鲶幼鱼的死亡存在一个敏感期.出现于内源性营养阶段进入混合性营养阶段,即孵化后的第4-10天内.幼鱼饲养中,水蚯蚓比枝角类生长要快. 相似文献
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饲料卵磷脂对花尾胡椒鲷幼鱼生长的影响 总被引：1，自引：0，他引：1
实验采用不同卵磷脂添加量[0，2，4，6，8，10：100（w／w饲料）]的配合饲料投喂花尾胡椒鲷（Plectorhynchus cinctus）幼鱼．对卵磷脂影响幼鱼生长存活的作用机制进行初步研究，投喂10d后，幼鱼体重随着饲料中卵磷脂添加量的增加而增加，而成活率则在添加量为4：100时最高．在添加卵磷脂组中，幼鱼蛋白酶活性基本上随着添加量的增加而增加，对照组的蛋白酶活性则异常地高；脂肪酶活性在卵磷脂添加量为2：100时最高，而后随着添加量的增加而下降；添加组的α-淀粉酶活性比对照组的高．饲料中添加卵磷脂可显著提高花尾胡椒鲷幼鱼Ca^2＋-ATPase和鳃Na^＋、K^＋-ATPase酶活性，且卵磷脂含量为2：100时Ca^2＋-ATPase和Na^＋、K^＋-ATPase活性最高．从结果看出，花尾胡椒鲷幼鱼的成活与Ca^2＋-ATPase和鳃Na^＋，K^＋-ATPase活性有关．生长与消化酶，尤其是蛋白酶活性有关。 相似文献
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两种常见农药对大弹涂鱼幼鱼的急性毒性研究 总被引：2，自引：0，他引：2
采用静态换水法检测了不同浓度下杀虫剂敌百虫和除草剂草甘膦对大弹涂鱼幼鱼的急性毒性．结果表明,大弹涂鱼幼鱼的死亡率随着农药浓度的升高而增加,并呈显著的相关关系;在水温24-28℃条件下,敌百虫对大弹涂鱼幼鱼48h和96h的半致死浓度（LC50）分别为1．25me4,和1．17mg/L,革甘膦对大弹涂鱼幼鱼48h和96h—LC50分别为335．47mg／L和308．55mg／L．显示了敌百虫和草甘膦对大弹涂鱼幼鱼具有一定潜在危害性． 相似文献
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尼加拉瓜鲡体鱼仔鱼开口饵料为轮虫或卤虫无节幼体，对饵料的选择总的趋势是随着仔稚鱼口径的增大和捕食能力的增强其所食的饵料生物由小变大。仔鱼对人工颗粒饵料无选择性。仔幼鱼的大小与所选择的饵料有关，即鱼的不同发育阶段（仔鱼、稚负、幼鱼）与所选择饵料种类有关． 相似文献
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介绍了天麻的生长发育过程和各生长发育阶段的营养特性,为天麻营养的研究和其人工种植的稳产高产提供参考． 相似文献
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健美牙齿最佳年龄
牙齿发育取决于两个阶段：一是从胎儿期2个月到出生．此为乳牙发育期，二是从出生后到8岁。为恒牙形成期。牙发育的质量与其他器官一样．营养优劣乃先决条件之一，钙、磷等矿物质与维生素D尤为重要． 相似文献
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教师每日工作紧张，节奏快，精神压力大，脑力劳动重．常无暇顾及饮食营养，容易引起营养缺乏。医学专家认为，教师应注意营养调配．保证充足的营养供给。 相似文献
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利用机器视觉系统获取养殖鱼摄食图像纹理特征来识别养殖鱼群的摄食行为。 从养殖鱼摄食图像上直接提取能表征鱼群摄食行为的20 维特征,通过归一化、PCA 降维和支持向量机训练获得养殖鱼摄食行为识别模型,以实现对养殖鱼摄食行为的识别。 结果表明,提出方法的平均精确度为92.3%、假负率7.34%、假正率4.15%,为指导养殖鱼智能投饵提供了参考。 相似文献
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Restrepo S 《Educational broadcasting international》1981,14(1):30-34
The breast feeding campaign in Colombia is particularly aimed at pregnant and feeding mothers in both urban and rural areas. The objectives are to: 1) encourage breast feeding; 2) lengthen the period of breast feeding; 3) delay the introduction of other foods, and 4) discourage the use of bottle feeding. The pregnant and feeding mothers were reached through doctors, nurses, nutritionists and educational agents. Seminars were organized to train health sector personnel. Curricula of university courses were revised. Printed materials such as handbooks, flipcharts and promotional posters were used. Games such as "Breastfeeding Ladder" were played in health centers. The use of mass media (radio, television, and films) was found to be the most effective method. Promotional advertising was aired on TV and radio. Films were used in 2 ways: short 10-minute films were produced and slide projection was introduced preceding the main feature film. The slide shows informed the mothers of the advantages of breast feeding. Some legal reforms were also made as part of the campaign: the Ministry of Health passed a resolution encouraging breast feeding in all its medical centers; the use of milk substitutes was prohibited; and promotion and packaging of milk substitutes were regulated by a decree. The success of this campaign can be measured by the increase in requests for advice on breast feeding in medical centers; the organizing in hospitals of specific programs for the promotion of breast feeding, and the move by advertising agencies to start promoting simultaneously their products and maternal milk. 相似文献
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针对微生物发酵补料生产中自动化程度低和补料量精度差的问题,提出一种基于AGA-BP的微生物发酵过程智能补料控制策略。基于微生物发酵过程的工艺特性,利用BP神经网络建立发酵过程的动态数学模型,并引入自适应遗传算法AGA对BP神经网络动态补料控制模型的权值进行优化。将建立的AGA-BP智能补料控制模型嵌入到ARM11控制器中,计算出当前最佳补料量,并通过无线传输模块对补料执行模块进行远程控制。实验结果表明,菌体浓度在AGA-BP补料策略控制下,相比人工补料提高了8.62%,相比未优化的BP神经网络提高了4.55%。因此,基于AGA-BP的补料策略具有更高的补料控制精度,有助于生物发酵实现自动化生产,提高发酵效率,降低生产成本。 相似文献
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马莹 《福建工程学院学报》2014,(3):220-224
中药粉剂配方下药系统是一个精度高、反应大滞后的系统,难以使用传统的方法进行下药控制。为有效实现中药粉剂快速、稳定、高精确度的下药问题,本文提出一种利用三次多项式加减速控制算法来实现在线分析医生处方上的中药粉剂配量,并通过Profibus光纤模块控制远程变频电机以计算所得运动曲线进行下药控制。实验结果验证了此方法的有效性。 相似文献
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设计了一种基于STC12C5A32S2单片机的选矿给料控制系统。该系统采用PWM/DC转换技术对变频器进行频率设定(0～120Hz),进而控制选矿给料系统的给料量,并以较少的按键实现了参数设置,同时运用单片机内部自带的A/D把核子秤测量的给料量大小(4～20mA的电流信号)进行实时显示。系统具有可靠性高、易于操作等特点。 相似文献
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Feeding Imprinting: The Extreme Test Case of Premature Infants Born With Very Low Birth Weight 
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下载免费PDF全文 Feeding imprinting, considered a survival‐enabling process, is not well understood. Infants born very preterm, who first feed passively, are an effective model for studying feeding imprinting. Retrospective analysis of neonatal intensive care unit (NICU) records of 255 infants (Mgestational age = 29.98 ± 1.64) enabled exploring the notion that direct breastfeeding (DBF) during NICU stay leads to consumption of more mother's milk and earlier NICU discharge. Results showed that DBF before the first bottle feeding is related to shorter transition into oral feeding, a younger age of full oral feeding accomplishment and earlier discharge. Furthermore, the number of DBF meals before first bottle feeding predicts more maternal milk consumption and improved NICU outcomes. Improved performance in response to initial exposure to DBF at the age of budding feeding abilities supports a feeding imprinting hypothesis. 相似文献